I use my laptop for a couple of hours at a time and the underside get REALLY hot. I cannot even touch it for more than a second or two. Yesterday, I propped the back side up with two decks of cards and then aimed a fan at the opening; did not help even a little. Any advice on what to do?

"You are not running off with Cow-Skull Man Dracula Skeletor!" -Socrates

(Yep, ninjaed) Dust is the probable reason. Seen that a lot when laptops have been used in the bedroomin bed ... you know what I mean, upon the bed. Sat on the duvet or blankets, fan drawing fine fibres anddead skin and dust mite droppings.

Someone who knows what they are doing (preferably) can probably check this and do a more thorough job by opening the case and giving it a good check, but ascertaining through the vent slots if the fan is spinning (if not, wouldn't be surprised if would have actually fried itself, but you might have been lucky so far) and then using clean dry air (don't accidentally spit in it! ...but blowing isn't that effective anyway) might do something to shift the cruft.

But if you have someone who can physically check it, better than my guesses.

You might also need to replace the thermoconductive paste between the processor and the cooler. If you feel brave and adventurous, there are a ton of disassembly videos on youtube. Bing your model + disassemble, then clean it and change the paste. Should hold for a year or so.

I'm going to go against the grain here and say that its not an insulation problem.

Consider this: if there were too much insulation (ie: dust) blocking the fans, the vast majority of CPUs will reach 100C and then shutoff due to thermal constraints. A "well insulated" laptop would keep the heat inside, and the heat would have a difficult time escaping. The same thing happens with modern GPUs, they're thermally limited to 100C (this may sound like a lot, but also remember that heatsinks are not 100% effective. Most CPUs / GPUs run at 60C+ typically, even though the fans / chassis is much cooler than that).

A well-ventilated laptop would transfer this heat to the outside very efficiently. IE: if you can feel the hot fans, its because they're working. If you feel heat coming out of the heatsink, its because the heatsink is working correctly. I guess in theory, the fans may have stopped working, so all of the heat is going through a secondary heatsink (aka: the bottom of the laptop, maybe?), but it sounds like the fans are hot and working as intended.

-----------

I think it is far more likely that a recent driver change... or possibly even a PCB-level manufacturing defect... has come into place, which is causing the overheating. IE: The CPUs / GPUs are hitting 100C for some reason all of a sudden. Maybe a virus has decided to start using your computer for BTC mining for example? Or maybe the motherboard degraded to the point where heat is being generated now.

But yeah, if you feel heat coming out of a laptop, that's because the cooling system is working correctly. Just like how you feel heat come out of a refrigerator... that's how cooling systems work. The heat has to go somewhere after all.

There is a difference between "air near the outlet vents is hot" and "other parts of the laptop are hot". I had an old laptop where the metal trim around the keyboard became untouchably hot - that was most definitely a dust issue.

UPDATE: I decided to open it up and remove any dust I found. To my complete surprise, I could not find any dust. Even more surprising, I could not find the fan! After I put it back together, some of the screws were missing abducted by aliens and it would not turn on anymore. Since this laptop is a hand-me-down from my younger brother, I am going to assume that he cannibalized the fan for some quick money and infected it with a virus designed to stop the computer from starting that activated when the laptop was opened. Really, it is Occam's Razor, which is, 'If you disagree with me I will gut you with a razor.'

"You are not running off with Cow-Skull Man Dracula Skeletor!" -Socrates

I have the opposite with opening up laptops: there are always screws left after putting it back together.

jewish_scientist wrote:Even more surprising, I could not find the fan!

Did you find an empty space near a heatsink (simple piece of metal) and an air duct? If not, it might be fanless by design or you didn't open it up far enough. If yes, it is related to the overheating problem.

jewish_scientist wrote:infected it with a virus designed to stop the computer from starting that activated when the laptop was opened.

There's always the possibility of damaging a wire or electr(on)ic component with your tools or your charged body. Or forgetting to plug one of the flatcables back in.Please get that blade away from me.

jewish_scientist wrote:If a computer gets to 113oF, should I get worried.

Less than you should if it gets to 113°R, but for different reasons.

It'd depend possibly the manufacturer/era of the component, but taking a popular site at face value..."You can check the specifications of your particular CPU at http://www.cpu-world.com which details the maximum operating temperature for many processors. In general you should consider 60 degrees Celcius [140°F] the absolute maximum for long periods, but aim for 45-50 degrees [113 to 122°F] to be safe." (My own Fahrenheit calculations, and bolding, E&OE.)

Soupspoon wrote:"You can check the specifications of your particular CPU at http://www.cpu-world.com which details the maximum operating temperature for many processors. In general you should consider 60 degrees Celcius [140°F] the absolute maximum for long periods, but aim for 45-50 degrees [113 to 122°F] to be safe." (My own Fahrenheit calculations, and bolding, E&OE.)

Really! I would have guessed that 100o F would be the safe limit. I guess they make this stuff better than I thought.

I looked up the model's design and found that it is not suppose to have a fan. Vents on the bottom are suppose to provide all the cooling necessary. When I took into considering that it does not even have MS Office installed, the flat cables are so short the laptop needs to almost be closed to plug them in and I have already the 2-3 files on it that I want backed up, I have decided to cannibalize it for parts and make my own computer from scratch. I have an older laptop (that only overheated when I blocked 2/3 of the vents for a couple hours) and my college has free computers in the library, so I am not rush to get a new one. I think I am going to head over to the thread on homemade desktops; I have always wanted to do that anyway. Thanks for all the help.

"You are not running off with Cow-Skull Man Dracula Skeletor!" -Socrates

jewish_scientist wrote:Really! I would have guessed that 100o F would be the safe limit. I guess they make this stuff better than I thought.

A tad over body temperature? That'd be a very low limit for electronic consumer goods (although also an improbably high one for deep-space IR telescope sensors).

Being fanless (saves on power, if it isn't instead using a Seebeck-effect cooler, and also much quieter!) it probably is a bit low-powered so as not to need the fan.

And if you don't require a laptop for its portibility, I'd stay away from them and indeed go for a desktop(/under-desk) computer. In laptops you pay a premium for the usually specially designed parts, which are often compromised for the sake of space/power requirements/heat dissipation and when a bit goes 'fizzzz!' that's often either the start of an expensive replacement hunt or you're getting a whole new laptop anyway... A servicable yet decent-spec standard immobile* PC can be repaired easier, eked out or updated with new (inexpensive!) bits easier and more of an old machine's more expensive bits can be used in (if not its next-generation replacement) another workaday machine that you might want to build in the future.

* Less likely to be dropped! Also coffee on the keyboard means, at worst, a new keyboard peripheral, not potentially having to clean, dry and test the motherboard beneath.

jewish_scientist wrote:Really! I would have guessed that 100o F would be the safe limit. I guess they make this stuff better than I thought.

A tad over body temperature? That'd be a very low limit for electronic consumer goods (although also an improbably high one for deep-space IR telescope sensors).

I think that you forgot the internate body temperature is ~100of. We prefer the outside temperature to be 70of. That means computers can function when 40-50 degrees higher than the expected environment. If they work just as well in the other direction, then they could literally be freezing without any problems.

And if you don't require a laptop for its portibility, I'd stay away from them and indeed go for a desktop(/under-desk) computer. In laptops you pay a premium for the usually specially designed parts, which are often compromised for the sake of space/power requirements/heat dissipation and when a bit goes 'fizzzz!' that's often either the start of an expensive replacement hunt or you're getting a whole new laptop anyway... A servicable yet decent-spec standard immobile* PC can be repaired easier, eked out or updated with new (inexpensive!) bits easier and more of an old machine's more expensive bits can be used in (if not its next-generation replacement) another workaday machine that you might want to build in the future.

* Less likely to be dropped! Also coffee on the keyboard means, at worst, a new keyboard peripheral, not potentially having to clean, dry and test the motherboard beneath.

I got it as a hand-me-down from my brother. Its is hard to get more for your money than free.

"You are not running off with Cow-Skull Man Dracula Skeletor!" -Socrates

jewish_scientist wrote:I think that you forgot the internate body temperature is ~100of.

You mean you don't take your computer internally? Or have I misunderstood how to use a Tablet PC?

I got it as a hand-me-down from my brother. Its is hard to get more for your money than free.

Can't argue with that, but unless you're going to get another family-rates gift, imminently, that's my general advice on what to spend your hard-earned money on...

For some reason, there's a public perception that "laptop equals better", when it'll just be left on the study desk day in, day out, and never really be used on the train or be necessary/practical/permitted/safe to bring into work every day, and for the luxury of potentially doing any of those things, you're likely paying more to do less and for a shorter time than a desktop would survive doing it.